Dual-sided radio-frequency package with overmold structure

ABSTRACT

A packaged radio-frequency device is disclosed, including a packaging substrate configured to receive one or more components, the packaging substrate including a first side and a second side. A shielded package may be implemented on the first side of the packaging substrate, the shielded package including a first circuit and a first overmold structure, the shielded package configured to provide radio-frequency shielding for at least a portion of the first circuit. A set of through-mold connections may be implemented on the second side of the packaging substrate, the set of through-mold connections defining a mounting volume on the second side of the packaging substrate. The device may include a component implemented within the mounting volume and a second overmold structure substantially encapsulating one or more of the component or the set of through-mold connections.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application claims priority to U.S. Provisional Application No.62/404,015 filed Oct. 4, 2016, entitled DUAL-SIDED RADIO-FREQUENCYPACKAGE WITH OVERMOLD STRUCTURE, and to U.S. Provisional Application No.62/404,022 filed Oct. 4, 2016, entitled RADIO-FREQUENCY DEVICE WITHDUAL-SIDED OVERMOLD STRUCTURE, and to U.S. Provisional Application No.62/404,029 filed Oct. 4, 2016, entitled CIRCUITS AND METHODS RELATED TORADIO-FREQUENCY DEVICES WITH DUAL-SIDED OVERMOLD STRUCTURE, thedisclosure of each of which is hereby expressly incorporated byreference herein in its entirety.

BACKGROUND

Field

The present disclosure generally relates to packaging of circuitdevices.

Description of the Related Art

The present disclosure relates to fabrication of packaged electronicmodules such as radio-frequency (RF) modules. In radio-frequency (RF)applications, RF circuits and related devices can be implemented in apackaged module. Such a packaged module can then be mounted on a circuitboard such as a phone board.

SUMMARY

In accordance with some implementations, the present disclosure relatesto a packaged radio-frequency (RF) device. The packaged radio-frequencydevice includes a packaging substrate configured to receive one or morecomponents, the packaging substrate including a first side and a secondside. The packaged radio-frequency device also includes a shieldedpackage implemented on the first side of the packaging substrate, theshielded package including a first circuit and a first overmoldstructure, and the shielded package configured to provideradio-frequency shielding for at least a portion of the first circuit.The packaged radio-frequency device further includes a set ofthrough-mold connections implemented on the second side of the packagingsubstrate, the set of through-mold connections defining a mountingvolume on the second side of the packaging substrate, a componentimplemented within the mounting volume and a second overmold structuresubstantially encapsulating one or more of the component or the set ofthrough-mold connections.

In some embodiments, at least a portion of the set of through-moldconnections is exposed through the second overmold structure. In someembodiments, the set of through-mold connections comprises a metallicmaterial. In some embodiments, the set of through-mold connectionscomprises a set of pillars configured to allow the packagedradio-frequency device to be mounted on a circuit board. In someembodiments, the first and second sides of the packaging substratecorrespond to upper and lower sides, respectively, when the packagedradio-frequency device is oriented to be mounted on a circuit board. Insome embodiments, the set of through-mold connections comprises a ballgrid array configured to allow the packaged radio-frequency device to bemounted on a circuit board.

In some embodiments, the ball grid array includes a first group ofsolder balls arranged to partially or fully surround the componentmounted on the lower side of the packaging substrate. In someembodiments, the ball grid array further includes a second group ofsolder balls arranged to partially or fully surrounds the first group ofsolder balls. In some embodiments, at least some of the first group ofsolder balls are electrically connected to input and output nodes of thefirst circuit. In some embodiments, each of the second group of solderballs is electrically connected to a ground plane within the packagingsubstrate.

In some embodiments, the first group of solder balls forms a rectangularperimeter around the component mounted on the lower side of thepackaging substrate. In some embodiments, the second group of solderballs forms a rectangular perimeter around the first group of solderballs.

In some embodiments, the packaging substrate includes a laminatesubstrate. In some embodiments, the packaging substrate includes aceramic substrate. In some embodiments, the ceramic substrate includes alow-temperature co-fired ceramic substrate.

In some embodiments, the first overmold structure substantiallyencapsulates the first circuit. In some embodiments, the shieldedpackage further includes an upper conductive layer implemented on thefirst overmold structure, the upper conductive layer electricallyconnected to a ground plane within the packaging substrate. In someembodiments, the electrical connection between the upper conductivelayer and a ground plane is achieved through one or more conductorswithin the first overmold structure.

In some embodiments, the one or more conductors include shieldingwirebonds arranged relative to the first circuit to provide RF shieldingfunctionality for at least a portion of the first circuit. In someembodiments, the one or more conductors include one or moresurface-mount technology devices mounted on the packaging substrate, theone or more surface-mount technology devices arranged relative to thefirst circuit to provide radio-frequency shielding functionality for atleast a portion of the first circuit.

In some embodiments, the electrical connection between the upperconductive layer and a ground plane is achieved through a conformalconductive coating implemented on one or more sides of the firstovermold structure. In some embodiments, the conformal conductivecoating extends to corresponding one or more sides of the packagingsubstrate.

In some embodiments, the packaging substrate includes one or moreconductive features each having a portion exposed at the correspondingside of the packaging substrate to form an electrical connection withthe conformal conductive coating, each conductive feature furtherconnected to the ground plane within the substrate packaging.

In some embodiments, the upper conductive layer is a conformalconductive layer. In some embodiments, the conformal conductive layersubstantially covers all four sides of the first overmold structure andall four sides of the packaging substrate. In some embodiments, theconformal conductive coating is implemented on one or more sides of thefirst overmold structure. In some embodiments, the conformal conductivelayer substantially covers all four sides of the first overmoldstructure.

In some embodiments, the component includes a surface-mount technologydevice. In some embodiments, the surface-mount technology deviceincludes a passive device or an active radio-frequency device. In someembodiments, the component includes a die. In some embodiments, the dieincludes a semiconductor die. In some embodiments, the semiconductor dieis configured to facilitate processing of radio-frequency signals by thefirst circuit.

The present disclosure also relates to a wireless device. The wirelessdevice includes a circuit board configured to receive a plurality ofpackaged modules. The wireless device further includes a shieldedradio-frequency module mounted on the circuit board, the radio-frequencymodule including a packaging substrate configured to receive a pluralityof components, the packaging substrate including a first side and asecond side, the radio-frequency module further including a shieldedpackage implemented on the first side of the packaging substrate, theshielded package including a first circuit and a first overmoldstructure, the shielded package configured to provide radio-frequencyshielding for at least a portion of the first circuit, theradio-frequency module further including a set of through-moldconnections implemented on the second side of the packaging substrate,the set of through-mold connections defining a mounting volume on thesecond side of the packaging substrate, the radio-frequency modulefurther including a component implemented within the mounting volume anda second overmold structure substantially encapsulating one or more ofthe component or the set of through-mold connections.

The present disclosure also relates to a method for manufacturingpackaged radio-frequency (RF) devices. The method includes providing apackaging substrate configured to receive a plurality of components, thepackaging substrate including a first side and a second side. The methodfurther includes forming a shielded package on the first side of thepackaging substrate, the shielded package including a first circuit anda first overmold structure, the shielded package configured to provideRF shielding for at least a portion of the first circuit. The methodfurther includes mounting a component on the second side of thepackaging substrate, and arranging a set of through-mold connections onthe second side of the packaging substrate such that the set ofthrough-mold connections is positioned relative to the component. Themethod also includes forming a second overmold structure over thecomponent and the set of through-mold connections and removing a portionof the second overmold structure.

In some embodiments, removing the portion of the second overmoldstructure comprises ablating the portion of the second overmoldstructure. In some embodiments, ablating the portion of the secondovermold structure exposes the set of through-mold connections throughthe second overmold structure. In some embodiments, removing the portionof the second overmold structure comprises removing portions of the setof through-mold connections. In some embodiments, removing the portionof the second overmold structure comprises removing a film of overmoldmaterial from the set of through-mold connections. In some embodiments,removing the portion of the second overmold structure comprises removingovermold material in areas surrounding the set of through-moldconnections.

In some embodiments, the first overmold structure substantiallyencapsulates the first circuit. In some embodiments, the set ofthrough-mold connections comprises a metallic material. In someembodiments, the set of through-mold connections is configured to allowthe packaged RF device to be mounted on a circuit board. In someembodiments, arranging the set of through-mold connections comprisesarranging a first group of through-mold connections to partially orfully surround the component mounted on the lower side of the packagingsubstrate. In some embodiments, arranging the set of through-moldconnections further comprises arranging a second group of through-moldconnections to partially or fully surround the first group ofthrough-mold connections.

In some embodiments, the method further includes electrically connectingat least some of the first group of through-mold connections to inputand output nodes of the first circuit. In some embodiments, the methodfurther includes electrically connecting at least some of the secondgroup of through-mold connections to a ground plane within the packagingsubstrate.

In some embodiments, the packaging substrate includes a laminatesubstrate. In some embodiments, the packaging substrate includes aceramic substrate. In some embodiments, the ceramic substrate includes alow-temperature co-fired ceramic (LTCC) substrate.

The present disclosure also relates to a method for manufacturingpackaged radio-frequency (RF) devices. The method includes providing apackaging substrate panel an array of units, the packaging substratepanel including a first side and a second side and forming a package onthe first side of the packaging substrate panel to yield a packagedpanel and such that each unit includes a first circuit and a firstovermold structure. The method further includes performing at least oneprocessing operation on the second side of the packaging substrate toyield a dual-sided panel, the second side of the packaging substrateincluding a second component and a second overmold structure. The methodalso includes singulating the dual-sided panel to yield a plurality ofindividual dual-sided packages and forming a conformal shielding layerfor each of the individual dual-sided packages arranged in a frame suchthat a conformal shielding layer covers an upper surface and at leastone side wall of the individual dual-sided package.

In some embodiments, the at least one processing operation on the secondside comprises mounting a component for each unit on the second side ofthe packaging substrate. In some embodiments, the at least oneprocessing operation on the second side further comprises arranging aset of through-mold connections for each unit relative to the componenton the second side of the packaging substrate. In some embodiments, theat least one processing operation on the second side further comprisesforming the second overmold structure over the component and the set ofthrough-mold connections. In some embodiments, the at least oneprocessing operation on the second side further comprises removing aportion of the second overmold structure.

In some embodiments, removing the portion of the second overmoldstructure comprises ablating the portion of the second overmoldstructure. In some embodiments, ablating the portion of the secondovermold structure exposes the set of through-mold connections throughthe second overmold structure. In some embodiments, removing the portionof the second overmold structure comprises removing portions of the setof through-mold connections. In some embodiments, removing the portionof the second overmold structure comprises removing a film of overmoldmaterial from the set of through-mold connections. In some embodiments,removing the portion of the second overmold structure comprises removingovermold material in areas surrounding the set of through-moldconnections.

In some embodiments, the set of through-mold connections comprises aball grid array (BGA). In some embodiments, the conformal shieldinglayer covers substantially all of the side walls of the individualdual-sided package. In some embodiments, each of the individualdual-sided packages is held on the frame by a tape. In some embodiments,the forming of the conformal shielding layer includes a sputterdeposition process.

In some embodiments, the frame has a rectangular shape configured tohold the individual dual-sided packages in a rectangular array. In someembodiments, the frame has a wafer-like format suitable for the sputterdeposition process. In some embodiments, the individual dual-sidedpackages are arranged in a selected ring region on the wafer-like frame.

The present disclosure relates to a method for manufacturing packagedradio-frequency (RF) devices. The method includes providing a packagingsubstrate configured to receive a plurality of components, the packagingsubstrate including a first side and a second side and forming ashielded package on the first side of the packaging substrate, theshielded package including a first circuit and a first overmoldstructure, the shielded package configured to provide RF shielding forat least a portion of the first circuit. The method further includesmounting a component on the second side of the packaging substrate andforming a second overmold structure over the component. The methodincludes forming a set of cavities in the second overmold structure, theset of cavities positioned relative to the component and forming a setof through-mold connections in the set of cavities in the secondovermold structure.

In some embodiments, the shielded package comprises a second overmoldstructure that substantially encapsulates the first circuit. In someembodiments, the set of through-mold connections comprises a metallicmaterial. In some embodiments, the set of through-mold connections isconfigured to allow the packaged RF device to be mounted on a circuitboard.

In some embodiments, forming the set of cavities comprises forming afirst group of cavities vias to partially or fully surround thecomponent mounted on the lower side of the packaging substrate. In someembodiments, forming the set of cavities further comprises forming asecond group of cavities to partially or fully surround the first groupof cavities. In some embodiments, the method further includeselectrically connecting at least some of the set of through-moldconnections to a ground plane within the packaging substrate. In someembodiments, the method further includes forming additional conductivematerial on the set of through-mold connections.

In some embodiments, the packaging substrate includes a laminatesubstrate. In some embodiments, the packaging substrate includes aceramic substrate. In some embodiments, the ceramic substrate includes alow-temperature co-fired ceramic (LTCC) substrate.

The present disclosure also relates to a method for manufacturingpackaged radio-frequency (RF) devices. The method includes providing apackaging substrate panel an array of units, the packaging substratepanel including a first side and a second side and forming a package onthe first side of the packaging substrate panel to yield a packagedpanel and such that each unit includes a first circuit and a firstovermold structure. The method further includes performing at least oneprocessing operation on the second side of the packaging substrate toyield a dual-sided panel, the second side of the packaging substrateincluding a second component and a second overmold structure andsingulating the dual-sided panel to yield a plurality of individualdual-sided packages.

In some embodiments, the method further includes forming a conformalshielding layer for each of the individual dual-sided packages arrangedin a frame such that a conformal shielding layer covers an upper surfaceand at least one side wall of the individual dual-sided package.

In some embodiments, the at least one processing operation on the secondside comprises mounting a component for each unit on the second side ofthe packaging substrate. In some embodiments, the at least oneprocessing operation on the second side further comprises forming asecond overmold structure over the component. In some embodiments, theat least one processing operation on the second side further comprisesforming a set of cavities in the second overmold structure, the set ofcavities positioned relative to the component. In some embodiments, theat least one processing operation on the second side further comprisesforming a set of through-mold connections in the set of cavities in thesecond overmold structure.

In some embodiments, the set of through-mold connections comprises aball grid array (BGA). In some embodiments, the conformal shieldinglayer covers substantially all of the side walls of the individualdual-sided package. In some embodiments, each of the individualdual-sided packages is held on the frame by a tape. In some embodiments,the forming of the conformal shielding layer includes a sputterdeposition process.

In some embodiments, the frame has a rectangular shape configured tohold the individual dual-sided packages in a rectangular array. In someembodiments, the frame has a wafer-like format suitable for the sputterdeposition process. In some embodiments, the individual dual-sidedpackages are arranged in a selected ring region on the wafer-like frame.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a dual-sided package having a shielded package and alower component mounted thereto, according to some implementations.

FIG. 2 illustrates a dual-sided package having a shielded package andone or more lower components mounted within a volume defined on anunderside of the shielded package, according to some implementations.

FIG. 3 illustrates a shielded package as a wire-shielded package,according to some implementations.

FIG. 4 illustrates a shielded package having a non-wire component thatprovides electrical connection between an upper conductive layer and aground plane within a packaging substrate, according to someimplementations.

FIG. 5 illustrates a shielded package having a conformal conductivelayer that is electrically connected to a ground plane within apackaging substrate, according to some implementations.

FIG. 6A illustrates a side view of a dual-sided package, according tosome implementations.

FIG. 6B illustrates an underside view of a dual-sided package, accordingto some implementations.

FIG. 6C illustrates a side view of a dual-sided package configured toprovide shielding functionality, according to some implementations.

FIG. 6D illustrates an underside view of a dual-sided package configuredto provide shielding functionality, according to some implementations.

FIG. 7A illustrates a dual-sided package implementing a BGA-mounteddevice and solder balls, according to some implementations.

FIG. 7B illustrates a dual-sided package implementing a BGA-mounteddevice and pillars, according to some implementations.

FIG. 8A illustrates a dual-sided package implementing a plurality oflower components, according to some implementations.

FIG. 8B illustrates a dual-sided package implementing a plurality oflower components, according to some implementations.

FIGS. 9A-9L illustrate various stages of fabrication processes forimplementing dual-sided packages, according to some implementations.

FIGS. 10A-10L illustrate various stages of fabrication processes forimplementing dual-sided packages, according to some implementations.

FIGS. 11A-11M illustrate various stages of fabrication processes forimplementing dual-sided packages, according to some implementations.

FIGS. 12A-12F illustrate various stages of fabrication processes forimplementing dual-sided packages, according to some implementations.

FIGS. 13A-13C illustrate various stages of forming dual-sided packageswithout conformal shielding, according to some implementations.

FIGS. 14A-14D illustrate various stages of processing individualpackages with a frame carrier, according to some implementations.

FIG. 15 illustrates a dual-sided package having one or moresurface-mount technology devices mounted on a packaging substrate,according to some implementations.

FIG. 16 illustrates another dual-sided package having one or moresurface-mount technology devices mounted on a packaging substrate,according to some implementations.

FIG. 17 illustrates another dual-sided package having one or moresurface-mount technology devices mounted on a packaging substrate,according to some implementations.

FIG. 18A illustrates a top-down perspective view of an underside of adual-sided package, according to some implementations.

FIG. 18B illustrates a top-down perspective view of an underside of adual-sided package, according to some implementations.

FIG. 18C illustrates a bottom-up close-up perspective view of a portionof an underside of a dual-sided package, according to someimplementations.

FIG. 19 illustrates a dual-sided package implemented as a diversityreceive module, according to some implementations.

FIG. 20 illustrates a dual-sided package implemented in a wirelessdevice, according to some implementations.

DETAILED DESCRIPTION OF SOME EMBODIMENTS

The headings provided herein, if any, are for convenience only and donot necessarily affect the scope or meaning of the claimed invention.

The present disclosure relates to fabrication of packaged electronicmodules such as radio-frequency (RF) modules. In radio-frequency (RF)applications, RF circuits and related devices can be implemented in apackaged module. Such a packaged module can then be mounted on a circuitboard such as a phone board.

FIG. 1 shows a dual-sided package 100 having a shielded package 102 anda lower component 104 mounted thereto. For the purpose of description, alower side of the shielded package 102 can include a side 103 of apackaging substrate that is to be mounted onto a circuit board such as aphone board. Although not shown separately in FIG. 1, it will beunderstood that the shielded package 102 can include such a packagingsubstrate and one or more upper components mounted on its upper side(when oriented as shown in FIG. 1). Accordingly, the dual-side propertycan include such upper component(s) mounted over the substrate and lowercomponent(s) mounted under the substrate.

For the purpose of description, it will be understood that a lowercomponent can include any device that can be mounted on the substrateand/or the circuit board. Such a device can be an active radio-frequency(RF) device or a passive device that facilitates processing of RFsignals. By way of non-limiting examples, such a device can include adie such as a semiconductor die, an integrated passive device (IPD), asurface-mount technology (SMT) device, and the like. In someembodiments, the lower component as described herein can be electricallycoupled to the one or more upper component through, for example, thesubstrate.

FIG. 2 shows that in some embodiments, one or more lower components canbe mounted under a shielded package, generally within a volume definedon an underside of the shielded package. In one embodiment, a set ofthrough-mold connections (e.g., one or more through-mold connections)may be implemented, formed, located, and/or positioned on the underside(e.g., side 103 illustrated in FIG. 1) of the shielded package 102. Theset of through-mold connections may define a volume on the underside ofthe shielded package 102. In FIG. 2, a volume 108 under a shieldedpackage 102 is shown to be defined by the underside of the shieldedpackage 102 and solder balls 106 of a ball grid array (BGA). The BGA maybe a set of through-mold connections. For example, each solder ball 106of the BGA may be a through-mold connection in the set of through-moldconnections. Other examples of through-mold connections include, but arenot limited to solder balls, pillars, columns, posts, pedestals, etc.The through-mold connections described herein may also be referred to ascontact features. The solder balls 106 are shown to allow the dual-sidedpackage 100 to be mounted on a circuit board 110 such as a phone board.The solder balls 106 can be configured so that when mounted to thecircuit board 110, there is sufficient vertical space between the uppersurface of the circuit board 110 and the lower surface of the shieldedpackage 102 for the lower component 104. As illustrated in FIG. 2, thevolume 108 is at least partially filled with an overmold 105. Theovermold 105 substantially encapsulates the lower component 104. In oneembodiment, at least a portion of the solder balls 106 may be exposedthrough the overmold 105. Exposing at least a portion of the solderballs 106 may provide a connection (e.g., an electrical and/or thermalconnection) through the overmold 105. For example, the solder balls 106may provide a connection (e.g., an electrical connection) to the lowercomponent 104 and/or components in the shield package 102. In oneembodiment, solder (or other conductive material) may be applied to theexposed portion of the solder balls 106 to form a connection (e.g.,electrical connection) with the circuit board 110. The overmold 105 mayalso be referred to as an overmold structure. In one embodiment, theovermold 105 and/or the solder balls 106 (e.g., the exposed portions ofthe solder balls 106) may form a land grid array (LGA) type/stylepackage.

A close-up view of the solder ball 106 is also illustrated in FIG. 2. Asillustrated in the close-up view of the solder ball 106, the bottom ofthe shielded package includes a pad 115. The pad 115 may be a metallicpad (or some other material) that may provide electrical and/or thermalconductivity between the solder ball 106 and components of the shieldpackage 102 and/or the lower component 104. Solder mask 114 may bedeposited over portions of the pad 115 to define a location where thesolder ball 106 may be formed. The solder ball 106 may be formed (e.g.,implemented, formed, dropped, etc.) on top of the pad 115 and the soldermask 114.

The dual-sided package 100 may be installed on the circuit board 110using the solder ball 106. The solder ball 106 may be attached to thecircuit board 110 (e.g., may be installed, mounted, fixed, etc., to thecircuit board 110) via connection 116. As illustrated in the close-upview of the solder ball 106, the connection 116 may include soldermaterial 121 and pad 119. The solder material 121 may be solder materialfrom the solder ball 106 that is deposited/melted onto the pad 119 whenthe dual-sided package 100 is attached to the circuit board. Forexample, during a reflow process, heat may be applied to melt at least aportion of the solder ball 106 to form the solder material 121. Thesolder material 121 may also include additional material that is formed,implemented, deposited, etc., over the solder ball 106. For example, thesolder material 121 may include solder material 118, illustrated inFIGS. 13B and 13C, and discussed in more detail below. The pad 119 maybe part of the circuit board 110. The pad 119 may provide electricaland/or thermal conductivity between the dual-sided package 100 and othercomponents/circuits attached to the circuit board 110 (not illustratedin the figures). In one embodiment, the pad 119 may include soldermaterial.

As illustrated in FIG. 2, the overmold 105 has a surface 112 (facingdownward toward the circuit board 110). In one embodiment, the surface112 may not contact (e.g., may not physically touch) the surface 113 ofthe circuit board 110. As illustrated in FIG. 2, a gap 109 is presentbetween the surface 112 and the surface 113. In one embodiment, the gap109 may help protect the lower component 104 from damage when there arelinear displacements of the dual-sided package 100 due to flexing ordropping. For example, the gap 109 may help protect the lower component104 from damage as the dual-sided package 100 is installed on thecircuit board 100 (e.g., may prevent the lower component 104 fromcontacting the surface 113 of the circuit board 110 duringinstallation/mounting of the dual-sided package). The portion of theovermold material 105 that covers the lower component 104 may provideadditional protection from damage when there are linear displacements ofthe dual-sided package 100 due to flexing or dropping. For example, theovermold material 105 may also prevent the lower component 104 fromcontacting the surface 113 of the circuit board 110 duringinstallation/mounting of the dual-sided package. In another embodiment,the gap 109 may also allow the dual-sided package to adapt toprocess/manufacturing variations when the dual-sided package 100 isinstalled on the circuit board 110. For example, different temperaturesmay be used to melt the solder ball 106 during installation of thedual-sided package. The gap 109 may help ensure that the dual-sidedpackage is properly installed by providing enough distance between thesurface 112 (of overmold 105) and the surface 113 (of circuit board 110)while still allowing the solder material of the solder ball 106 toproperly bond with the pad 119 of the circuit board 110. In someembodiments, although the overmold 105 and/or the gap 109 may preventthe component 104 from contacting the surface 113 (of the circuit board110), the dual-sided package 100 and/or the component 104 may stilloperate/function properly even if the component 104 does contact thesurface 113. For example, the component 104 may remain undamaged and/oroperable even after contacting the surface 113 of the circuit board 110.

Examples related to fabrication of dual-sided packages having such aconfiguration are described herein in greater detail. It will beunderstood that although such examples are described in the context ofsolder balls, other types of connection features that provide sufficientvertical space can also be utilized. Although the embodiments, examples,configurations, and/or implementations disclosed herein may refer tosolder balls and/or a BGA, one having ordinary skill in the artunderstands that solder balls and/or a BGA are examples of through-moldconnections. One having ordinary skill in the art understands that othertypes of through-mold connections (e.g., pillars, columns, etc.,) may beused to define a volume on an underside of a shielded package and anovermold may be implemented in the volume (on the underside of theshielded package). In one embodiment, a through-mold connection (or aset of through-mold connections) may be any structure and/or componentthat may be used to define a volume on the underside of a shieldedpackage and/or may be used to support the shielded package above asurface.

Examples of Dual-Sided Packages with BGA

FIGS. 3-6 show non-limiting examples of dual-sided packages having BGAs.FIGS. 3-5 show examples of configurations of shielded packages that canbe utilized. FIGS. 6A and 6B show an example of a BGA configuration thatcan be implemented. FIGS. 6C and 6D show an example of a pillar based(e.g., post, column) configuration that can be implemented.

FIG. 3 shows that in some embodiments, the shielded package 102 of FIG.2 can be a wire-shielded package 120. The wire-shielded package 120 isshown to include a packaging substrate 122 (e.g., a laminate substrate)and a plurality of components mounted thereon. For example, a firstcomponent 124 is depicted as being mounted on the upper surface of thepackaging substrate 122, and electrical connections between thecomponent 124 and the packaging substrate 122 can be facilitated by, forexample, wirebonds 128. In another example, a second component 126 isshown to be mounted on the upper surface of the packaging substrate 122in a die-attach configuration. Electrical connections between thecomponent 126 and the packaging substrate 122 can be facilitated by, forexample, die-attach features.

In the example of FIG. 3, a plurality of shielding wires 130 (e.g.shielding wirebonds) are shown to be provided over the packagingsubstrate 122. Such shielding wires 130 can be electrically connected toa ground plane (not shown) within the packaging substrate 122. Theshielding wires 130 as well as the mounted components 124, 126 are shownto be encapsulated by an overmold 132. The upper surface of the overmold132 can be configured to expose the upper portions of the shieldingwires 130, and an upper conductive layer 134 can be formed thereon.Accordingly, a combination of the upper conductive layer 134, theshielding wires 130, and the ground plane can define a shielded volumeor region. Such a configuration can be implemented to provide shieldingfunctionality between regions within and outside of the shielded package120, and/or between regions that are both within the shielded package120. Additional details concerning such shielding can be found in, forexample, U.S. Pat. No. 8,373,264 entitled SEMICONDUCTOR PACKAGE WITHINTEGRATED INTERFERENCE SHIELDING AND METHOD OF MANUFACTURE THEREOFwhich is expressly incorporated by reference in its entirety for allpurposes.

In the example of FIG. 3, an array of solder balls 106 is shown to beimplemented on the underside of the packaging substrate 122 so as todefine an underside volume. A lower component 104 is shown to be mountedwithin such an underside volume to thereby form a dual-sided package100. An overmold 105 may be formed and/or implemented in the undersidevolume (where the lower component 104 is located) formed by the solderballs 106 (e.g., formed by a set of through-mold connections, such as aBGA). In one embodiment, the overmold 105 may encapsulate at least aportion of the lower component 104. For example, the overmold 105 mayfully or partially encapsulate the lower component 104. In anotherembodiment, the overmold 105 may encapsulate at least a portion of thesolder balls 106 (e.g., through-mold connections). For example, theovermold 105 may fully or partially encapsulate the solder balls 106. InFIG. 3, the dual-sided package 100 is shown to be mounted on a circuitboard 110 such as a phone board. As discussed above, the overmold 105and/or the solder balls 106 (e.g., the exposed portions of the solderballs 106) may form a land grid array (LGA) type/style package. Asillustrated in FIG. 3, the solder balls 106 may have a semicircularshape. For example, the bottom portion of the solder balls 106 may beremoved to form the semicircular shape. The semicircular shape of thesolder balls 106 may be formed during a manufacturing process, asdiscussed in more detail below.

As illustrated in FIG. 3, the dual-sided package 100 may be attached tothe circuit board 110 via connections 116. A close-up view of the solderballs 106 and the connections 116, and additional details (of the solderballs 106 and the connections 116) are illustrated/discussed above inconjunction with FIG. 2. Also as illustrated in FIG. 3, a gap 109 ispresent between the surface 112 and the surface 113 of the circuit board110. The gap 109 may help protect the lower component 104 from damagewhen there are linear displacements of the dual-sided package 100 due toflexing or dropping, as discussed above. The gap 109 may also allow thedual-sided package to adapt to process/manufacturing variations when thedual-sided package 100 is installed on the circuit board 110, asdiscussed above.

FIG. 4 shows that in some embodiments, the shielded package 102 of FIG.2 can be a shielded package 140 having a non-wire component 150 thatprovides electrical connection between an upper conductive layer 154 anda ground plane (not shown) within a packaging substrate 142 (e.g., alaminate substrate). In addition to the component 150, the packagingsubstrate 142 is shown to have a plurality of components mountedthereon. For example, a first component 144 is depicted as being mountedon the upper surface of the packaging substrate 142, and electricalconnections between the component 144 and the packaging substrate 142can be facilitated by, for example, wirebonds 148. In another example, asecond component 146 is shown to be mounted on the upper surface of thepackaging substrate 142 in a die-attach configuration. Electricalconnections between the component 146 and the packaging substrate 142can be facilitated by, for example, die-attach features.

In the example of FIG. 4, the component 150 is shown to provide anelectrical connection between the upper conductive layer 154 and theground plane (not shown) within the packaging substrate 142. Thecomponent 150 as well as the mounted components 144, 146 are shown to beencapsulated by an overmold 152. The upper surface of the overmold 152can be configured to expose the upper portion of the component 150, andthe upper conductive layer 154 can cover such an exposed portion as wellas the remaining upper surface of the overmold 152. Accordingly, acombination of the upper conductive layer 154, the component 150, andthe ground plane can define a shielded volume or region. Such aconfiguration can be implemented to provide shielding functionalitybetween regions within and outside of the shielded package 140, and/orbetween regions that are both within the shielded package 140.Additional details concerning such shielding can be found in, forexample, U.S. patent application Ser. No. 14/252,719 filed on Apr. 14,2014, entitled APPARATUS AND METHODS RELATED TO CONFORMAL COATINGIMPLEMENTED WITH SURFACE MOUNT DEVICES, which is expressly incorporatedby reference in its entirety.

In the example of FIG. 4, an array of solder balls 106 is shown to beimplemented on the underside of the packaging substrate 142 so as todefine an underside volume. A lower component 104 is shown to be mountedwithin such an underside volume to thereby form a dual-sided package100. An overmold 105 may be formed and/or implemented in the undersidevolume (where the lower component 104 is located) formed by the solderballs 106 (e.g., formed by a set of through-mold connections, such as aBGA). In one embodiment, the overmold 105 may encapsulate at least aportion of the lower component 104. For example, the overmold 105 mayfully or partially encapsulate the lower component 104. In anotherembodiment, the overmold 105 may encapsulate at least a portion of thesolder balls 106 (e.g., through-mold connections). For example, theovermold 105 may fully or partially encapsulate the solder balls 106. InFIG. 4, the dual-sided package 100 is shown to be mounted on a circuitboard 110 such as a phone board. As discussed above, the overmold 105and/or the solder balls 106 (e.g., the exposed portions of the solderballs 106) may form a land grid array (LGA) type/style package. Asillustrated in FIG. 4, the solder balls 106 may have a semicircularshape. For example, the bottom portion of the solder balls 106 may beremoved to form the semicircular shape. The semicircular shape of thesolder balls 106 may be formed during a manufacturing process, asdiscussed in more detail below.

As illustrated in FIG. 4, the dual-sided package 100 may be attached tothe circuit board 110 via connections 116. A close-up view of the solderballs 106 and the connections 116, and additional details (of the solderballs 106 and the connections 116) are illustrated/discussed above inconjunction with FIG. 2. Also as illustrated in FIG. 3, a gap 109 ispresent between the surface 112 and the surface 113 of the circuit board110. The gap 109 may help protect the lower component 104 from damagewhen there are linear displacements of the dual-sided package 100 due toflexing or dropping, as discussed above. The gap 109 may also allow thedual-sided package to adapt to process/manufacturing variations when thedual-sided package 100 is installed on the circuit board 110, asdiscussed above.

FIG. 5 shows that in some embodiments, the shielded package 102 of FIG.2 can be a shielded package 160 having a conformal conductive layer 174that is electrically connected to a ground plane (not shown) within apackaging substrate 162 (e.g., a laminate substrate or a ceramicsubstrate). The packaging substrate 162 is shown to have a plurality ofcomponents mounted thereon. For example, a first component 164 isdepicted as being mounted on the upper surface of the packagingsubstrate 162, and electrical connections between the component 164 andthe packaging substrate 162 can be facilitated by, for example,wirebonds 168. In another example, a second component 166 is shown to bemounted on the upper surface of the packaging substrate 162 in adie-attach configuration. Electrical connections between the component166 and the packaging substrate 162 can be facilitated by, for example,die-attach features.

In the example of FIG. 5, the mounted components 164, 166 are shown tobe encapsulated by an overmold 172. The conformal conductive layer 174is shown to generally cover the upper surface of the overmold 172, aswell as side walls (e.g., all four side walls) defined by the sides ofthe overmold 172 and the packaging substrate 162. The packagingsubstrate 162 is shown to include conductive features 170 havingportions exposed on the sides of the packaging substrate, and alsoelectrically connected to the ground plane (not shown), to therebyprovide electrical connections between the conformal conductive layer174 and the ground plane. Accordingly, a combination of the conformalconductive layer 174 and the ground plane can define a shielded volumeor region. Such a configuration can be implemented to provide shieldingfunctionality on one or more sides of the shielded package 160.Additional details concerning such shielding can be found in, forexample, U.S. patent application Ser. No. 14/528,447 filed on Oct. 30,2014, entitled DEVICES AND METHODS RELATED TO PACKAGING OFRADIO-FREQUENCY DEVICES ON CERAMIC SUBSTRATES, which is also expresslyincorporated by reference in its entirety for all purposes. In someembodiments, the overmold 172 may not be present (e.g., the overmold 172may be optional). For example, when the packaging substrate 162 is aceramic substrate, the overmold 172 may not be present.

In the example of FIG. 5, an array of solder balls 106 is shown to beimplemented on the underside of the packaging substrate 162 so as todefine an underside volume. A lower component 104 is shown to be mountedwithin such an underside volume to thereby form a dual-sided package100. An overmold 105 may be formed and/or implemented in the undersidevolume (where the lower component 104 is located) formed by the solderballs 106 (e.g., formed by a set of through-mold connections, such as aBGA). In one embodiment, the overmold 105 may encapsulate at least aportion of the lower component 104. For example, the overmold 105 mayfully or partially encapsulate the lower component 104. In anotherembodiment, the overmold 105 may encapsulate at least a portion of thesolder balls 106 (e.g., through-mold connections). For example, theovermold 105 may fully or partially encapsulate the solder balls 106. InFIG. 5, the dual-sided package 100 is shown to be mounted on a circuitboard 110 such as a phone board. As discussed above, the overmold 105and/or the solder balls 106 (e.g., the exposed portions of the solderballs 106) may form a land grid array (LGA) type/style package. Asillustrated in FIG. 5, the solder balls 106 may have a semicircularshape. For example, the bottom portion of the solder balls 106 may beremoved to form the semicircular shape. The semicircular shape of thesolder balls 106 may be formed during a manufacturing process, asdiscussed in more detail below.

As illustrated in FIG. 5, the dual-sided package 100 may be attached tothe circuit board 110 via connections 116. A close-up view of the solderballs 106 and the connections 116, and additional details (of the solderballs 106 and the connections 116) are illustrated/discussed above inconjunction with FIG. 2. Also as illustrated in FIG. 3, a gap 109 ispresent between the surface 112 and the surface 113 of the circuit board110. The gap 109 may help protect the lower component 104 from damagewhen there are linear displacements of the dual-sided package 100 due toflexing or dropping, as discussed above. The gap 109 may also allow thedual-sided package to adapt to process/manufacturing variations when thedual-sided package 100 is installed on the circuit board 110, asdiscussed above.

In the examples of FIGS. 3-5, the solder balls 106 are depicted as beingimplemented in a single row that forms a perimeter at an underside ofthe shielded package. If such solder balls are utilized as input and/oroutput for processing of radio-frequency (RF) signals, it may bedesirable to provide shielding between such input/output solder ballsand locations outside of the dual-sided package 100. Furthermore, itshall be understood that in other embodiments, any of the shieldingfeatures of FIGS. 3, 4, and/or 5 may be combined. For example, two ormore of the shielding wires 130 illustrated in FIG. 3, the component 150illustrated in FIG. 4, and the conformal conductive layer 174illustrated in FIG. 5, may be combined.

FIGS. 6A and 6B show side and underside views of a dual-sided package100 configured to provide such shielding functionality. In the exampleof FIGS. 6A and 6B, two rows of solder balls can be implemented. Theinner row of solder balls 106 a can be utilized for input and/or outputof RF signals, or for any other input/output where shielding is desired.The outer row of solder balls 106 b can be utilized for, for example,grounding of the dual-sided package 100, and can be electricallyconnected to the ground plane of the shielded package 102. Accordingly,the outer row of solder balls 106 b can provide shielding for the innerrow of solder balls 106 a. The outer row of solder balls 106 b can alsoprovide shielding for the lower component 104.

In the example of FIGS. 6A and 6B, each of the inner and outer rows ofsolder balls 106 a, 106 b is shown to form a full perimeter on theunderside of the shielded package 102. However, it will be understoodthat either or both of the inner and outer rows of solder balls 106 a,106 b can form partial perimeter(s) as needed or desired to achievedesired functionalities. For example, if shielding is desired on onlyone side, a full perimeter of the outer row of solder balls 106 b maynot be needed. Accordingly, one or more sides of outer row of solderballs 106 b can be implemented to provide such shielding functionality.In another example, input/output connections (e.g., RF input/output,control signals, power) may not need a full perimeter of inner row ofsolder balls 106 a. Accordingly, the inner row of solder balls 106 a canform a partial perimeter on the underside of the shielded package 102.Furthermore, the examples of FIGS. 6A and 6B may illustrate views of thedual-sided package 100 before the overmold (e.g., overmold 105illustrated in FIG. 2) is implemented and/or formed on the underside ofthe shielded package 102.

FIGS. 6C and 6D show side and underside views of a dual-sided package100 configured to provide such shielding functionality. In the exampleof FIGS. 6C and 6D, two rows of pillars (e.g., columns, posts, etc.) canbe implemented. The inner row of pillars 111 a can be utilized for inputand/or output of RF signals, or for any other input/output whereshielding is desired. The outer row of pillars 111 b can be utilizedfor, for example, grounding of the dual-sided package 100, and can beelectrically connected to the ground plane of the shielded package 102.Accordingly, the outer row of pillars 111 b can provide shielding forthe inner row of pillars 111 a. The outer row of pillars 111 b can alsoprovide shielding for the lower component 104.

In the example of FIGS. 6C and 6D, each of the inner and outer rows ofpillars 111 a, 111 b is shown to form a full perimeter on the undersideof the shielded package 102. However, it will be understood that eitheror both of the inner and outer rows of pillars 111 a, 111 b can formpartial perimeter(s) as needed or desired to achieve desiredfunctionalities. For example, if shielding is desired on only one side,a full perimeter of the outer row of pillars 111 b may not be needed.Accordingly, one or more sides of outer row of pillars 111 b can beimplemented to provide such shielding functionality. In another example,input/output connections (e.g., RF input/output, control signals, power)may not need a full perimeter of inner row of pillars 111 a.Accordingly, the inner row of pillars 111 a can form a partial perimeteron the underside of the shielded package 102. Furthermore, the examplesof FIGS. 6C and 6D may illustrate views of the dual-sided package 100before the overmold (e.g., overmold 105 illustrated in FIG. 2) isimplemented and/or formed on the underside of the shielded package 102.

Examples of Additional Features in Dual-Sided Packages

FIG. 7A illustrates a dual-sided package 100 that is similar to theBGA-based example of FIG. 2. An overmold 105 may be formed and/orimplemented in the underside volume (where the lower component 104 islocated) formed by the solder balls (e.g., formed by a set ofthrough-mold connections, such as a BGA). In one embodiment, theovermold 105 may encapsulate at least a portion of the lower component104. For example, the overmold 105 may fully or partially encapsulatethe lower component 104. In another embodiment, the overmold 105 mayencapsulate at least a portion of the solder balls (e.g., through-moldconnections). For example, the overmold 105 may fully or partiallyencapsulate the solder balls. As discussed above, the overmold 105and/or the solder balls 106 (e.g., the exposed portions of the solderballs 106) may form a land grid array (LGA) type/style package. Asillustrated in FIG. 7A, the solder balls 106 may have a semicircularshape. For example, the bottom portion (e.g., bottom half) of the solderballs 106 may be removed to form the semicircular shape. Thesemicircular shape of the solder balls 106 may be formed during amanufacturing process, as discussed in more detail below. In oneembodiment, exposing a portion of the solder balls 106 through theovermold 105 may allow the solder balls 106 to provide a connection(e.g., a through-mold connection, an electrical connection) tocomponents of the dual-sided package 100. A close-up view of the solderballs 106 and additional details (of the solder balls 106) areillustrated/discussed above in conjunction with FIG. 2.

FIG. 7B illustrates a pillar-based example of a dual-sided package 100.An overmold 105 may be formed and/or implemented in the underside volume(where the lower component 104 is located) formed by the pillars 111(e.g., through-mold connections). In one embodiment, the overmold 105may encapsulate at least a portion of the lower component 104. Forexample, the overmold 105 may fully or partially encapsulate the lowercomponent 104. In another embodiment, the overmold 105 may encapsulateat least a portion of the pillars 111. Portions of the pillars 111(e.g., the upper surfaces of the pillars 111) may be exposed through theovermold 105. As discussed above, the overmold 105 and/or the pillars111 may form a land grid array (LGA) type/style package. In oneembodiment, exposing a portion of the pillars 111 through the overmold105 may allow the pillars 111 to provide a connection (e.g., athrough-mold connection, an electrical connection) to components of thedual-sided package 100.

FIG. 8A shows that in some embodiments, a dual-sided package can includea plurality of lower components. In FIG. 8A, a dual-sided package 100 issimilar to the BGA-based example of FIG. 2. The dual-sided package 100is shown to include two lower components 104 a, 104 b mounted to theunderside of a shielded package 102. An overmold 105 may be formedand/or implemented in the underside volume (where the lower components104 a and 104 b are located) formed by the solder balls (e.g., formed bya set of through-mold connections, such as a BGA). In one embodiment,the overmold 105 may encapsulate at least a portion of the lowercomponent 104. For example, the overmold 105 may fully or partiallyencapsulate the lower component 104. In another embodiment, the overmold105 may encapsulate at least a portion of the solder balls (e.g.,through-mold connections). For example, the overmold 105 may fully orpartially encapsulate the solder balls. As discussed above, the overmold105 and/or the solder balls 106 (e.g., the exposed portions of thesolder balls 106) may form a land grid array (LGA) type/style package.As illustrated in FIG. 8A, the solder balls 106 may have a semicircularshape. For example, the bottom portion of the solder balls 106 may beremoved to form the semicircular shape. The semicircular shape of thesolder balls 106 may be formed during a manufacturing process, asdiscussed in more detail below. In one embodiment, exposing a portion ofthe solder balls 106 through the overmold 105 may allow the solder balls106 to provide a connection (e.g., a through-mold connection, anelectrical connection) to components of the dual-sided package 100. Aclose-up view of the solder balls 106 and additional details (of thesolder balls 106) are illustrated/discussed above in conjunction withFIG. 2.

FIG. 8B shows that in some embodiments, a dual-sided package can includea plurality of lower components. In FIG. 8B, the dual-sided package 100may be a pillar-based example. The dual-sided package 100 is shown toinclude two lower components 104 a, 104 b mounted to the underside of ashielded package 102. An overmold 105 may be formed and/or implementedin the underside volume (where the lower components 104 a and 104 b arelocated) formed by the pillars 111 (e.g., through-mold connections). Inone embodiment, the overmold 105 may encapsulate at least a portion ofthe lower component 104. For example, the overmold 105 may fully orpartially encapsulate the lower component 104. In another embodiment,the overmold 105 may encapsulate at least a portion of the solder balls.Portions of the pillars 111 (e.g., the upper surfaces of the pillars111) may be exposed through the overmold 105. As discussed above, theovermold 105 and/or the pillars 111 may form a land grid array (LGA)type/style package. In one embodiment, exposing a portion of the pillars111 through the overmold 105 may allow the pillars 111 to provide aconnection (e.g., a through-mold connection, an electrical connection)to components of the dual-sided package.

Other additional features, variations, or any combination thereof, canbe also be implemented.

Examples Related to Fabrication of Dual-Sided Packages

FIGS. 9-14 show examples of how dual-sided packages can be fabricated.As described herein, such examples can facilitate mass-production ofdual-sided packages.

FIGS. 9-13 show various stages of a fabrication process in whichsubstantially all of dual-sided features can be implemented in a panelformat having an array of to-be-separated units, before such units areseparated (also referred to as singulated). Although described in thecontext of BGA-based and/or pillar (e.g., column, posts, etc.) baseddual-sided packages, it will be understood that one or more features ofthe fabrication technique of FIGS. 9-13 can also be implemented forfabrication of dual-sided packages having other types of mountingfeatures. In some implementations, the fabrication processes of FIGS.9-14 can be utilized for manufacturing of dual-sided packages describedherein in reference to, for example, FIGS. 3, 4, 5, 7A, 7B, 8A, 8B, 15,16, and/or 17.

Referring to FIG. 9A, a fabrication state 250 a can include a panel 252having a plurality of to-be-singulated units. For example, singulationcan occur at boundaries depicted by dashed lines 260 so at to yieldsingulated individual units. The panel 252 is shown to include asubstrate panel 254 on which upper portions (collectively indicated as256) are formed. Each unit of such an upper-portion panel can includevarious parts described herein in reference to FIGS. 3, 4, and/or 5. Forexample, each unit of such an upper-portion panel may include shieldingfeatures of FIGS. 3, 4, and/or 5. Such parts can include variouscomponents and shielding structures mounted or implemented on thesubstrate panel 254. The upper-portion panel 256 can also include anovermold layer which can be formed as a common layer for a number ofindividual units. Similar to the common overmold layer, an upperconductive layer 258 can be formed to cover a number of individualunits.

Referring to FIG. 9B, a fabrication state 262 a can include the panel252 of FIG. 9A being inverted so that its underside faces upward. Suchan inverted orientation can allow processing of the underside while theindividual units are still attached in the panel.

Referring to FIG. 9C, a fabrication state 263 a can include a lowercomponent 104 being attached for each unit on the underside (which isfacing upward) of the substrate 254. The fabrication state 263 a mayalso include an array of solder balls 106 being formed for each unit onthe underside (which is facing upward) of the substrate 254. Such a stepis shown to yield an array of dual-sided units to be singulated. It willbe understood that the lower component 104 may be attached for each unit(on the underside) after the array of solder balls 106 is formed, orvice versa. It shall also be understood that the lower component (foreach unit on the underside) and the array of solder balls 106 may beattached, implemented, and/or formed substantially simultaneously.

Referring to FIG. 9D, a fabrication state 264 a can include implementingand/or forming overmold 105 on the underside (which is facing upward) ofthe substrate 254. In one embodiment, the overmold 105 may completelyencapsulate the lower component 104 and the solder balls 106 (e.g., thethrough-mold connections) in the fabrication state 264 a.

Referring to FIG. 9E, a fabrication state 266 a can include removing atleast a portion of the overmold 105. For example, an outward surface(e.g., the upper surface) of the overmold 105 may be removed. Removingat least the portion of the overmold 105 may expose the solders balls106 through the overmold 105. For example, the overmold 105 maypartially encapsulate the solder balls 106 after the portion of theovermold 105 is removed. The portion of the overmold 105 may be removedusing various different types of processes and/or methods. For example,the overmold 105 may be ground (with an abrasive surface) to remove theportion of the overmold 105 (to expose a portion of the solder balls106). In another example, the portion of the overmold 105 may be removedusing a laser to melt and/or burn the portion of the overmold 105 (toexpose a portion of the solder balls 106). In a further example, theportion of the overmold 105 may be ablated. For example, a stream ofparticles (e.g., water particles, sand particles, etc.) may be used toerode the portion of the overmold 105. In one embodiment, removing theportion of the overmold 105 may also remove a portion of the solderballs 106. For example, ablating the overmold 105 may remove the topportions of the solder balls 106 to form the semicircular shapeillustrated in FIGS. 9E and 9F. This may also expose a portion of thesolder balls 106 through the overmold 105 and may allow the solder balls106 to provide a connection (e.g., an electrical connection) through theovermold 105.

Referring to FIG. 9F, a fabrication state 268 a can include individualunits being singulated to yield a plurality of dual-sided packages 100substantially ready to be mounted to circuit boards. It will beunderstood that such a singulation process can be achieved while thepanel (252) is in its inverted orientation (as shown in the example ofFIG. 9E), or while the panel (252) is in its upright orientation (e.g.,as in the example of FIG. 9A). A close-up view of the solder balls 106and additional details (of the solder balls 106) areillustrated/discussed above in conjunction with FIG. 2.

Referring to FIG. 9G, a fabrication state 250 b can include a panel 252having a plurality of to-be-singulated units. For example, singulationcan occur at boundaries depicted by dashed lines 260 so at to yieldsingulated individual units. The panel 252 is shown to include asubstrate panel 254 on which upper portions (collectively indicated as256) are formed. Each unit of such an upper-portion panel can includevarious parts described herein in reference to FIGS. 3, 4, and/or 5. Forexample, each unit of such an upper-portion panel may include shieldingfeatures of FIGS. 3, 4, and/or 5. Such parts can include variouscomponents and shielding structures mounted or implemented on thesubstrate panel 254. The upper-portion panel 256 can also include anovermold layer which can be formed as a common layer for a number ofindividual units. Similar to the common overmold layer, an upperconductive layer 258 can be formed to cover a number of individualunits.

Referring to FIG. 9H, a fabrication state 262 b can include the panel252 of FIG. 9A being inverted so that its underside faces upward. Suchan inverted orientation can allow processing of the underside while theindividual units are still attached in the panel.

Referring to FIG. 9I, a fabrication state 263 b can include a lowercomponent 104 being attached for each unit on the underside (which isfacing upward) of the substrate 254. The fabrication state 263 b mayalso include an array of pillars 111 being formed for each unit on theunderside (which is facing upward) of the substrate 254. Such a step isshown to yield an array of dual-sided units to be singulated. It will beunderstood that the lower component 104 may be attached for each unit(on the underside) after the array of pillars 111 are formed, or viceversa. It shall also be understood that the lower component (for eachunit on the underside) and the array of pillars 111 may be attached,implemented, and/or formed substantially simultaneously. The pillars 111may be formed using various methods, processes, technologies, etc., suchas copper pillar bumping.

Referring to FIG. 9J, a fabrication state 264 b can include implementingand/or forming overmold 105 on the underside (which is facing upward) ofthe substrate 254. In one embodiment, the overmold 105 may completelyencapsulate the lower component 104 and the pillars 111 (e.g., thethrough-mold connections) in the fabrication state 264 b.

Referring to FIG. 9K, a fabrication state 266 b can include removing atleast a portion of the overmold 105. For example, an outward surface(e.g., the upper surface) of the overmold 105 may be removed. Removingat least the portion of the overmold 105 may expose the solders balls106 through the overmold 105. For example, the overmold 105 maypartially encapsulate the solder balls 106 after the portion of theovermold 105 is removed. The portion of the overmold 105 may be removedusing various different types of processes and/or methods. For example,the overmold 105 may be ground (with an abrasive surface) to remove theportion of the overmold 105 (to expose a portion of the solder balls106). In another example, the portion of the overmold 105 may be removedusing a laser to melt and/or burn the portion of the overmold 105 (toexpose a portion of the solder balls 106). In a further example, theportion of the overmold 105 may be ablated. For example, a stream ofparticles (e.g., water particles, sand particles, etc.) may be used toerode the portion of the overmold 105. In one embodiment, removing theportion of the overmold 105 may also remove a portion of the pillars111. For example, ablating the overmold 105 may remove the top portionsof the pillars 111. This may also expose a portion of the pillars 111through the overmold 105 and may allow the pillars 111 to provide aconnection (e.g., an electrical connection) through the overmold 105.

Referring to FIG. 9L, a fabrication state 268 b can include individualunits being singulated to yield a plurality of dual-sided packages 100substantially ready to be mounted to circuit boards. It will beunderstood that such a singulation process can be achieved while thepanel (252) is in its inverted orientation (as shown in the example ofFIG. 9K), or while the panel (252) is in its upright orientation (e.g.,as in the example of FIG. 9G).

As described herein, such processing of most or all of upper and lowersides of a substrate panel can be achieved since the side walls of thedual-sided packages are not utilized for shielding. However, when one ormore side walls include shielding features, at least some of processingrelated to shielding need to be implemented with the corresponding sidewalls exposed. In some embodiments (e.g., where all four side wallsinclude shielding features), at least some processing need to beperformed on singulated units.

Examples Related to Processing of Individual Units

In the examples described in reference to FIGS. 9A-9L, FIGS. 10-10L,FIGS. 11A-11M, FIGS. 12A-12F, and FIGS. 13A-13C, substantially all stepsin fabrication of dual-sided packages can be performed in a panel formatbefore individual units are singulated. For the examples of FIGS.14A-14D, the forming of the conductive layer on each unit may beperformed after a singulation step/process.

FIGS. 10-10L, FIGS. 11A-11M, FIGS. 12A-12F, FIGS. 13A-13C and FIGS.14A-14D show examples related a process for manufacturingconformal-shielded dual-sided packages. In such a process, singulationcan be performed after process steps (e.g., mounting of a lowercomponent and formation of a BGA) are performed on the underside of apackaging substrate. More particularly, FIGS. 10-10L, FIGS. 11A-11M,FIGS. 12A-12F, and FIGS. 13A-13C show various example states leading toformation of dual-sided packages without conformal shielding. FIGS.14A-14D show examples related to how conformal shielding can be formedfor such dual-sided packages.

In some embodiments, the examples process steps of FIGS. 10A-10F can besimilar to the examples of FIGS. 9A-9F, but without the conductive layer(258). Referring to FIG. 10A, a fabrication state 350 a can include apanel 352 having a plurality of to-be-singulated units. For example,singulation can occur at boundaries depicted by dashed lines 360 so atto yield singulated individual units. The panel 352 is shown to includea substrate panel 354 on which upper portions (collectively indicated as356) are formed. Each unit of such an upper-portion panel can includevarious parts described herein in reference to any combination of FIGS.3, 4, and 5. Such parts can include various components and shieldingstructures mounted or implemented on the substrate panel 354. Theupper-portion panel 356 can also include an overmold layer which can beformed as a common layer for a number of individual units. In theexample of FIG. 10A, conductive features 378 are shown to be implementedwithin the substrate panel 354. Each conductive feature 378 can straddlethe corresponding boundary 360, such than when separation occurs at theboundary 360, each of the two exposed side walls of the substratesincludes an exposed portion of the conductive feature 378 that has beencut. Each of such cut conductive feature is electrically connected to aground plane (not shown) within the corresponding substrate.

Referring to FIG. 10B, a fabrication state 362 a can include the panel352 of FIG. 10A being inverted so that its underside faces upward. Suchan inverted orientation can allow processing of the underside while theindividual units are still attached in the panel.

Referring to FIG. 10C, a fabrication state 364 a can include a lowercomponent 104 being attached for each unit on the underside (which isfacing upward) of the substrate 354. Fabrication state 364 a can alsoinclude an array of solder balls 106 being formed for each unit on theunderside (which is facing upward) of the substrate 354. It shall beunderstood that the lower component 104 may be attached for each unit(on the underside) after the array of solder balls 106 is formed, orvice versa. It shall also be understood that the lower component 104(for each unit on the underside) and the array of solder balls 106 maybe attached, implemented, and/or formed substantially simultaneously.

Referring to FIG. 10D, a fabrication state 366 a can includeimplementing an overmold 105 over the array of solder balls 106 and thelower components 104. In one embodiment, the overmold 105 may completelyencapsulate the lower component 104 and the solder balls 106 (e.g., thethrough-mold connections) in the fabrication state 366 a.

Referring to FIG. 10E, a fabrication state 367 a can include removing atleast a portion of the overmold 105. For example, an outward surface(e.g., the upper surface) of the overmold 105 may be removed. Removingat least the portion of the overmold 105 may expose the solders balls106 through the overmold 105. For example, the overmold 105 maypartially encapsulate the solder balls 106 after the portion of theovermold 105 is removed. The portion of the overmold 105 may be removedusing various different types of processes and/or methods. For example,the overmold 105 may be ground (with an abrasive surface) to remove theportion of the overmold 105 (to expose a portion of the solder balls106). In another example, the portion of the overmold 105 may be removedusing a laser to melt and/or burn the portion of the overmold 105 (toexpose a portion of the solder balls 106). In a further example, theportion of the overmold 105 may be ablated. For example, a stream ofparticles (e.g., water particles, sand particles, etc.) may be used toerode the portion of the overmold 105. Such a step is shown to yield anarray of un-shielded dual-sided units to be singulated. In oneembodiment, removing the portion of the overmold 105 may also remove aportion of the solder balls 106. For example, ablating the overmold 105may remove the top portions of the solder balls 106 to form thesemicircular shape illustrated in FIGS. 10E and 10F. This may alsoexpose a portion of the solder balls 106 through the overmold 105 andmay allow the solder balls 106 to provide a connection (e.g., anelectrical connection) through the overmold 105.

Referring to FIG. 10F, a fabrication state 368 a can include individualunits being singulated to yield a plurality of un-shielded dual-sidedpackages 370 substantially ready for conformal shielding process steps,or if shielding is not needed, substantially ready to be mounted tocircuit boards. As described above, each of the dual-sided packages 370includes side walls; and each side wall is shown to include an exposedportion of the cut conductive feature 378. In some embodiments, such asingulation process can be achieved while the panel (352) is in itsinverted orientation (as shown in the example of FIG. 10E), or while thepanel (352) is in its upright orientation (e.g., as in the example ofFIG. 10A). A close-up view of the solder balls 106 and additionaldetails (of the solder balls 106) are illustrated/discussed above inconjunction with FIG. 2.

In some embodiments, the examples process steps of FIGS. 10G-10L can besimilar to the examples of FIGS. 9G-9L, but without the conductive layer(258). Referring to FIG. 10G, a fabrication state 350 b can include apanel 352 having a plurality of to-be-singulated units. For example,singulation can occur at boundaries depicted by dashed lines 360 so atto yield singulated individual units. The panel 352 is shown to includea substrate panel 354 on which upper portions (collectively indicated as356) are formed. Each unit of such an upper-portion panel can includevarious parts described herein in reference to any combination of FIGS.3, 4, and 5. Such parts can include various components and shieldingstructures mounted or implemented on the substrate panel 354. Theupper-portion panel 356 can also include an overmold layer which can beformed as a common layer for a number of individual units. In theexample of FIG. 10G, conductive features 378 are shown to be implementedwithin the substrate panel 354. Each conductive feature 378 can straddlethe corresponding boundary 360, such than when separation occurs at theboundary 360, each of the two exposed side walls of the substratesincludes an exposed portion of the conductive feature 378 that has beencut. Each of such cut conductive feature is electrically connected to aground plane (not shown) within the corresponding substrate.

Referring to FIG. 10H, a fabrication state 362 b can include the panel352 of FIG. 10G being inverted so that its underside faces upward. Suchan inverted orientation can allow processing of the underside while theindividual units are still attached in the panel.

Referring to FIG. 10I, a fabrication state 364 b can include a lowercomponent 104 being attached for each unit on the underside (which isfacing upward) of the substrate 354. Fabrication state 364 b can alsoinclude an array of pillars 111 being formed for each unit on theunderside (which is facing upward) of the substrate 354. It shall beunderstood that the lower component 104 may be attached for each unit(on the underside) after the array of pillars 111 is formed, or viceversa. It shall also be understood that the lower component 104 (foreach unit on the underside) and the array of pillars 111 may beattached, implemented, and/or formed substantially simultaneously.

Referring to FIG. 10J, a fabrication state 366 b can includeimplementing an overmold 105 over the array of pillars 111 and the lowercomponents 104. In one embodiment, the overmold 105 may completelyencapsulate the lower component 104 and the pillars 111 (e.g., thethrough-mold connections) in the fabrication state 366 b.

Referring to FIG. 10K, a fabrication state 367 b can include removing atleast a portion of the overmold 105. For example, an outward surface(e.g., the upper surface) of the overmold 105 may be removed. Removingat least the portion of the overmold 105 may expose the pillars 111through the overmold 105. For example, the overmold 105 may partiallyencapsulate the pillars 111 after the portion of the overmold 105 isremoved. The portion of the overmold 105 may be removed using variousdifferent types of processes and/or methods. For example, the overmold105 may be ground (with an abrasive surface) to remove the portion ofthe overmold 105 (to expose a portion of the pillars 111). In anotherexample, the portion of the overmold 105 may be removed using a laser tomelt and/or burn the portion of the overmold 105 (to expose a portion ofthe pillars 111). In a further example, the portion of the overmold 105may be ablated. For example, a stream of particles (e.g., waterparticles, sand particles, etc.) may be used to erode the portion of theovermold 105. Such a step is shown to yield an array of un-shieldeddual-sided units to be singulated. In one embodiment, removing theportion of the overmold 105 may also remove a portion of the pillars111. For example, ablating the overmold 105 may remove the top portionsof the pillars 111. This may also expose a portion of the pillars 111through the overmold 105 and may allow the pillars 111 to provide aconnection (e.g., an electrical connection) through the overmold 105.

Referring to FIG. 10L, a fabrication state 368 a can include individualunits being singulated to yield a plurality of un-shielded dual-sidedpackages 370 substantially ready for conformal shielding process steps,or if shielding is not needed, substantially ready to be mounted tocircuit boards. As described above, each of the dual-sided packages 370includes side walls; and each side wall is shown to include an exposedportion of the cut conductive feature 378. In some embodiments, such asingulation process can be achieved while the panel (352) is in itsinverted orientation (as shown in the example of FIG. 10K), or while thepanel (352) is in its upright orientation (e.g., as in the example ofFIG. 10G).

FIGS. 11A-11G show various example states leading to formation ofdual-sided packages without conformal shielding. Referring to FIG. 11A,a fabrication state 1105 can include a panel 352 having a plurality ofto-be-singulated units. For example, singulation can occur at boundariesdepicted by dashed lines 360 so at to yield singulated individual units.The panel 352 is shown to include a substrate panel 354 on which upperportions (collectively indicated as 356) are formed. Each unit of suchan upper-portion panel can include various parts described herein inreference to any combination of FIGS. 3, 4, and 5. Such parts caninclude various components and shielding structures mounted orimplemented on the substrate panel 354. The upper-portion panel 356 canalso include an overmold layer which can be formed as a common layer fora number of individual units. In the example of FIG. 11A, conductivefeatures 378 are shown to be implemented within the substrate panel 354.Each conductive feature 378 can straddle the corresponding boundary 360,such than when separation occurs at the boundary 360, each of the twoexposed side walls of the substrates includes an exposed portion of theconductive feature 378 that has been cut. Each of such cut conductivefeature is electrically connected to a ground plane (not shown) withinthe corresponding substrate.

Referring to FIG. 11B, a fabrication state 1110 can include the panel352 of FIG. 11A being inverted so that its underside faces upward. Suchan inverted orientation can allow processing of the underside while theindividual units are still attached in the panel.

Referring to FIG. 11C, a fabrication state 1115 can include a lowercomponent 104 being attached for each unit on the underside (which isfacing upward) of the substrate 354. For example, the lower component104 may be mounted, installed, etc., to the underside of the substrate354. The lower component 104 may be directly attached to the substrateor may be attached to other components (e.g., one or more metal pads) onthe substrate 354.

Referring to FIG. 11D, a fabrication state 1120 can include implementingan overmold 105 over the lower components 104. In one embodiment, theovermold 105 may completely encapsulate the lower component 104 in thefabrication state 1120.

Referring to FIG. 11E, a fabrication state 1125 can include forming aplurality of cavities 1126 (e.g., holes, voids, spaces, gaps, etc.) inthe overmold 105. The cavities 1126 may have a partial conical shape(e.g., a cone shape with the top and bottom portions of the coneremoved). As illustrated in FIG. 11E, the cavities 1126 may have atrapezoidal shape when viewed from the side (e.g., a profile view). Onehaving ordinary skill in the art understands that the cavities 1126 mayhave various sizes and/or shapes. For example, the cavities 1126 may becylinder shaped, cubed shaped, trapezoid prism shaped, etc. In oneembodiment, the cavities 1126 may be forming using a laser (e.g., alaser drill). For example, a laser may be used to burn and/or meltportions of the overmold 105 to form the cavities 1126. One havingordinary skill in the art understands that various other methods,processes, and/or operations may be used to form the cavities 1126.

Referring to FIG. 11F, a fabrication state 1130 can include forming aplurality of solder balls 106 (e.g., through-mold connections) withinthe cavities 1126. For example, solder material (e.g., a conductivematerial that may melt at a certain temperature) may be deposited intothe cavities 1126. In one embodiment, the height of the solder balls 106may be lower than the height of the overmold 105. In another embodiment,the height of the solder balls may be equal (or substantially equal) tothe height of the overmold 105. In another embodiment, the height of thesolder may be higher than the height of the overmold 105. As illustratedin FIG. 11F, there may be a gap between the overmold 105 and the top ofthe solder balls 106. For example, the angle of the sides of thecavities 1126 (e.g., the side walls of the cavities 1126) may result inthe gap between the overmold 105 and the top of the solder balls 106.This may be due to the shape/size of the cavities 1126 and theshape/size of the solder balls 106. In other embodiments, the gapbetween the overmold 105 and the top of the solder balls 106 may belarger, smaller, or may not be present, based on the shape/size of thecavities 1126 and the shape/size of the solder balls 106.

Referring to FIG. 11G, a fabrication state 1135 can include individualunits being singulated to yield a plurality of un-shielded dual-sidedpackages 1190 substantially ready for conformal shielding process steps,or if shielding is not needed, substantially ready to be mounted tocircuit boards. As described above, each of the dual-sided packages 1190includes side walls; and each side wall is shown to include an exposedportion of the cut conductive feature 378. In some embodiments, such asingulation process can be achieved while the panel (352) is in itsinverted orientation (as shown in the example of FIG. 11F), or while thepanel (352) is in its upright orientation (e.g., as in the example ofFIG. 11A). A close-up view of the solder balls 106 and additionaldetails (of the solder balls 106) are illustrated/discussed above inconjunction with FIG. 2.

FIGS. 11H-11M show various example states leading to formation ofdual-sided packages without conformal shielding. Referring to FIG. 11H,a fabrication state 1155 can include a panel 352 having a plurality ofto-be-singulated units. For example, singulation can occur at boundariesdepicted by dashed lines 360 so at to yield singulated individual units.The panel 352 is shown to include a substrate panel 354 on which upperportions (collectively indicated as 356) are formed. Each unit of suchan upper-portion panel can include various parts described herein inreference to any combination of FIGS. 3, 4, and 5. Such parts caninclude various components and shielding structures mounted orimplemented on the substrate panel 354. The upper-portion panel 356 canalso include an overmold layer which can be formed as a common layer fora number of individual units. In the example of FIG. 11H, conductivefeatures 378 are shown to be implemented within the substrate panel 354.Each conductive feature 378 can straddle the corresponding boundary 360,such than when separation occurs at the boundary 360, each of the twoexposed side walls of the substrates includes an exposed portion of theconductive feature 378 that has been cut. Each of such cut conductivefeature is electrically connected to a ground plane (not shown) withinthe corresponding substrate.

Referring to FIG. 11I, a fabrication state 1160 can include the panel352 of FIG. 11A being inverted so that its underside faces upward. Suchan inverted orientation can allow processing of the underside while theindividual units are still attached in the panel.

Referring to FIG. 11J, a fabrication state 1165 can include a lowercomponent 104 being attached for each unit on the underside (which isfacing upward) of the substrate 254. The fabrication state 1165 may alsoinclude an array of solder balls 106 being formed for each unit on theunderside (which is facing upward) of the substrate 254. Such a step isshown to yield an array of dual-sided units to be singulated. It will beunderstood that the lower component 104 may be attached for each unit(on the underside) after the array of solder balls 106 is formed, orvice versa. It shall also be understood that the lower component (foreach unit on the underside) and the array of solder balls 106 may beattached, implemented, and/or formed substantially simultaneously.

Referring to FIG. 11K, a fabrication state 1170 can include implementingan overmold 105 over the lower components 104 and the solder balls 106.In one embodiment, the overmold 105 may completely encapsulate the lowercomponent 104 in the fabrication state 1120. In another embodiment, theovermold 105 may completely encapsulate the solder balls 106. Forexample, the height of the overmold 105 may be higher than the height ofthe solder balls 106. In a further embodiment, the height of theovermold 105 may be equal (or substantially equal) to the height of thesolder balls.

Referring to FIG. 11L, a fabrication state 1125 can include removingportions of the overmold 105 in areas that are around the solder balls106 (e.g., around the through-mold connections). For example, portionsof the overmold 105 in a circular area (centered around a solder ball106) may be removed (e.g., a circular portion of the overmold 105centered around a solder ball 106 may be removed). As illustrated inFIG. 11L, there may be a gap between the overmold 105 and the top of thesolder balls 106. One having ordinary skill in the art understands thatthe portions of the overmold 105 that are removed may have various sizesand/or shapes. For example, a square shaped portion of the overmoldcentered around a solder ball 106 may be removed. In one embodiment,portions of the overmold 105 may be removed using a laser (e.g., a laserdrill). For example, a laser may be used to burn and/or melt portions ofthe overmold 105 in the areas around the solder balls 106. One havingordinary skill in the art understands that various other methods,processes, and/or operations may be used to remove portions of theovermold 105. As illustrated in FIG. 11L, there may be a gap between theovermold 105 and the top of the solder balls 106. In other embodiments,the gap between the overmold 105 and the top of the solder balls 106 maybe larger, smaller, or may not be present.

Referring to FIG. 11M, a fabrication state 1135 can include individualunits being singulated to yield a plurality of un-shielded dual-sidedpackages 1195 substantially ready for conformal shielding process steps,or if shielding is not needed, substantially ready to be mounted tocircuit boards. As described above, each of the dual-sided packages 1195includes side walls; and each side wall is shown to include an exposedportion of the cut conductive feature 378. In some embodiments, such asingulation process can be achieved while the panel (352) is in itsinverted orientation (as shown in the example of FIG. 11L), or while thepanel (352) is in its upright orientation (e.g., as in the example ofFIG. 11H). A close-up view of the solder balls 106 and additionaldetails (of the solder balls 106) are illustrated/discussed above inconjunction with FIG. 2.

FIGS. 12A-12F show various example states leading to formation ofdual-sided packages without conformal shielding. Referring to FIG. 12A,a fabrication state 1205 can include a panel 352 having a plurality ofto-be-singulated units. For example, singulation can occur at boundariesdepicted by dashed lines 360 so at to yield singulated individual units.The panel 352 is shown to include a substrate panel 354 on which upperportions (collectively indicated as 356) are formed. Each unit of suchan upper-portion panel can include various parts described herein inreference to any combination of FIGS. 4, 5, and 5. Such parts caninclude various components and shielding structures mounted orimplemented on the substrate panel 354. The upper-portion panel 356 canalso include an overmold layer which can be formed as a common layer fora number of individual units. In the example of FIG. 12A, conductivefeatures 378 are shown to be implemented within the substrate panel 354.Each conductive feature 378 can straddle the corresponding boundary 360,such than when separation occurs at the boundary 360, each of the twoexposed side walls of the substrates includes an exposed portion of theconductive feature 378 that has been cut. Each of such cut conductivefeature is electrically connected to a ground plane (not shown) withinthe corresponding substrate.

Referring to FIG. 12B, a fabrication state 1210 can include the panel352 of FIG. 12A being inverted so that its underside faces upward. Suchan inverted orientation can allow processing of the underside while theindividual units are still attached in the panel.

Referring to FIG. 12C, a fabrication state 1265 can include a lowercomponent 104 being attached for each unit on the underside (which isfacing upward) of the substrate 254. The fabrication state 1265 may alsoinclude an array of solder balls 106 being formed for each unit on theunderside (which is facing upward) of the substrate 254. Such a step isshown to yield an array of dual-sided units to be singulated. It will beunderstood that the lower component 104 may be attached for each unit(on the underside) after the array of solder balls 106 is formed, orvice versa. It shall also be understood that the lower component (foreach unit on the underside) and the array of solder balls 106 may beattached, implemented, and/or formed substantially simultaneously.

Referring to FIG. 12D, a fabrication state 1270 can include implementingan overmold 105 over the lower components 104 and the solder balls 106.In one embodiment, the overmold 105 may completely encapsulate the lowercomponent 104 in the fabrication state 1220. The overmold 105 may alsosubstantially encapsulate the solder balls 106. For example, asillustrated in the close-up view of solder ball 106, the height of theovermold 105 may be shorter than the height of the solder ball 106 butthe majority of the solder ball 106 may be encapsulated by the overmold105. In one embodiment, a layer 117 (e.g., a film, a coating, a thinsheet, etc.) of overmold material may be deposited on the tops of thesolder balls 106 after the overmold 105 is implemented over the lowercomponents 104 and the solder balls 106.

Referring to FIG. 12E, a fabrication state 1225 can include removing thelayer 117 (e.g., the film of overmold material) from the tops of thesolder balls 106. For example, a laser may be used to burn and/or meltthe layer 117 from the top of a solder ball 106. One having ordinaryskill in the art understands that various other methods, processes,and/or operations may be used to remove the layer 117. As illustrated inFIG. 12E, there may be a gap between the overmold 105 and the top of thesolder balls 106 after removing the layer 117. In other embodiments, thegap between the overmold 105 and the top of the solder balls 106 may belarger, smaller, or may not be present.

Referring to FIG. 12F, a fabrication state 1230 can include individualunits being singulated to yield a plurality of un-shielded dual-sidedpackages 1290 substantially ready for conformal shielding process steps,or if shielding is not needed, substantially ready to be mounted tocircuit boards. As described above, each of the dual-sided packages 1290includes side walls; and each side wall is shown to include an exposedportion of the cut conductive feature 378. In some embodiments, such asingulation process can be achieved while the panel (352) is in itsinverted orientation (as shown in the example of FIG. 12E), or while thepanel (352) is in its upright orientation (e.g., as in the example ofFIG. 12A). A close-up view of the solder balls 106 and additionaldetails (of the solder balls 106) are illustrated/discussed above inconjunction with FIG. 2.

FIGS. 13A-13C show various example states leading to formation ofdual-sided packages without conformal shielding. Referring to FIG. 13A,a fabrication state 1305 may include a panel 352 with solder balls 106,components 104, and an overmold 105 implemented on a substrate panel354, as discussed above. Upper portions (collectively indicated as 356)may be formed on the substrate panel 354, as discussed above. Forexample, the panel 352 may result from the fabrication state 1130illustrated in FIG. 11F, the fabrication state 1175 illustrated in FIG.11L, and/or the fabrication state 12E illustrated in FIG. 12E. In theexample of FIG. 13A, conductive features 378 are shown to be implementedwithin the substrate panel 354. Each conductive feature 378 can straddlethe corresponding boundary 360, such than when separation occurs at theboundary 360, each of the two exposed side walls of the substratesincludes an exposed portion of the conductive feature 378 that has beencut. Each of such cut conductive feature is electrically connected to aground plane (not shown) within the corresponding substrate.

Referring to FIG. 13B, a fabrication state 1310 may include forming,depositing, implementing, etc., conductive material 118 on top of thesolder balls 106. For example additional solder balls may be formed ontop of the solder balls 106. In another example, solder material may bescreen printed on top of the solder balls 106. The additional conductivematerial may be used to attach the dual-sided packages to a surface(e.g., to a circuit board). The additional conductive material may alsoprovide electrical connections and/or thermal conductivity betweencomponents/circuits of the dual-sided packages and/or othercomponents/circuits (e.g., between components/circuits located on acircuit board).

Referring to FIG. 13C, a fabrication state 1315 can include individualunits being singulated to yield a plurality of un-shielded dual-sidedpackages 1390 substantially ready for conformal shielding process steps,or if shielding is not needed, substantially ready to be mounted tocircuit boards. As described above, each of the dual-sided packages 1390includes side walls; and each side wall is shown to include an exposedportion of the cut conductive feature 378. In some embodiments, such asingulation process can be achieved while the panel (352) is in itsinverted orientation (as shown in the example of FIG. 13A), or while thepanel (352) is in its upright orientation. A close-up view of the solderballs 106 and additional details (of the solder balls 106) areillustrated/discussed above in conjunction with FIG. 2.

Examples Related to Conformal Coating

FIGS. 14A-14D show various states of a process that can be implementedto process individual units such as the un-shielded dual-sided packages370 of FIG. 10D with a frame carrier 300. Referring to FIG. 14A, afabrication state 380 can include a plurality of un-shielded dual-sidedpackages 370 being positioned (arrow 382) over an adhesive layer 320.Examples of the adhesive layer 320 may include a layer of glue, a layerof paste, a layer of epoxy/epoxy resin, etc. The adhesive layer 320 maybe deposited over a surface 321 of the frame carrier 300 (e.g., an uppersurface of the frame carrier 300). A close-up view of the solder balls106 and additional details (of the solder balls 106) areillustrated/discussed above in conjunction with FIG. 2.

Referring to FIG. 14B, a fabrication state 383 can include theun-shielded dual-sided packages 370 positioned such that the solderballs 106 and/or a surface of the overmold on the underside of thepackaging substrate (e.g., overmold 105 illustrated in FIG. 2) engage(e.g., are in contact with) the surface 321. As illustrated in FIG. 14B,the solder balls 106 may engage the surface of the adhesive layer 320.Such an engagement between the lower surface of the dual-sided packages370 and the surface 321 is indicated as 388. Also as illustrated in FIG.14B, the overmold 105 on the underside of the packaging substrate mayengage adhesive layer 320 (e.g., may contact the adhesive layer 320).Such an engagement between the overmold 105 on the underside of thepackaging substrate and the adhesive layer 320 is indicated as 386.

Once the individual un-shielded dual-sided packages 370 are arranged insuch a manner, some or all of the subsequent steps can be performed inmanners as if the units are in a panel format. Advantageously, suchsteps can include formation of a conformal shielding layer on the uppersurface and the side walls (390) of each un-shielded dual-sided package370. More particularly, and as described herein, the position of theun-shielded dual-sided package 370 relative to the plate 304 allows theside walls 390 to be exposed substantially fully for metal deposition bytechniques such as sputter deposition. As further shown in FIG. 14B, theun-shielded dual-sided packages 370 can be arranged so that theun-shielded dual-sided packages 370 positioned therein are spaced apartsufficiently to facilitate effective sputter deposition of metal on theside walls 390.

FIG. 14C shows a fabrication state 384 where a conformal conductivelayer 385 has been formed. Such a conformal conductive layer 385 isshown to cover the upper surface and the side walls (390) of eachdual-sided package. The side wall portion of the conformal conductivelayer 385 is further shown to be in electrical contact with theconductive features 378 (which are in turn connected to a ground plane(not shown)) to thereby form an RF shield for the dual-sided package.

FIG. 14D shows a fabrication state 386 where shielded dual-sidedpackages 100 are being removed (arrow 387) from the frame carrier 300.Thus, one can see that the resulting dual-sided packages 100 withconformal shielding can be obtained by different processes. For example,the dual-sided packages 100 with conformal shielding as described inreference to FIG. 14D are similar to the dual-sided packages 100 (withconformal shielding) of FIG. 14D. Accordingly, it will be understoodthat other variations in process steps can be implemented.

In one embodiment, portions of the adhesive layer 320 may remainattached (e.g., may stick) to the shielded dual-sided packages 100 whenthe shielded dual-sided packages 100 are removed (not shown in thefigures). The portions of the adhesive layer 320 that remain attached tothe shielded dual-sided packages 100 may be removed in a later process.For example, the portions of the adhesive layer 320 that remain attachedto the shielded dual-sided packages 100 may be removed during a cleaningprocess.

Examples of Products Related to Dual-Sided Packages

As described herein, a shielded package and a lower component of adual-sided package can include different combinations of components.FIG. 15 shows that in some embodiments, a dual-sided package 100 caninclude a shielded package 102 having one or more surface-mounttechnology (SMT) devices 400 mounted on a packaging substrate 402. Asfurther shown in FIG. 15, one or more semiconductor die 104 can bemounted under the packaging substrate 402. As described herein, such oneor more die can be mounted within a region generally defined by an arrayof solder balls 106.

As further described herein, an overmold 404 can be formed over thepackaging substrate 402 so as to substantially encapsulate the SMTdevice(s) 404, and to facilitate shielding functionalities. It will beunderstood that the shielded package 102 can include one or moreshielding features as described herein. An overmold 105 may be formedand/or implemented in the underside volume (where the semiconductor die104 is located) formed by the solder balls 106 (e.g., formed by a set ofthrough-mold connections, such as a BGA). In one embodiment, theovermold 105 may encapsulate at least a portion of the semiconductor die104. For example, the overmold 105 may fully or partially encapsulatethe semiconductor die 104. In another embodiment, the overmold 105 mayencapsulate at least a portion of the solder balls 106 (e.g.,through-mold connections). For example, the overmold 105 may fully orpartially encapsulate the solder balls 106. As discussed above, theovermold 105 and/or the solder balls 106 (e.g., the exposed portions ofthe solder balls 106) may form a land grid array (LGA) type/stylepackage. A close-up view of the solder balls 106 and additional details(of the solder balls 106) are illustrated/discussed above in conjunctionwith FIG. 2.

FIG. 16 shows a dual-sided package 100 that can be a more specificexample of the dual-sided package of FIG. 15. In the example of FIG. 16,the SMT device(s) can be one or more filters and/or filter-based devices400 that are encapsulated by an overmold 404. Further, the semiconductordie 104 mounted under a packaging substrate 402 can be a die having RFamplifier(s) and/or switch(es). Accordingly, such a dual-side packagecan be implemented as different modules configured to facilitatetransmission and/or reception of RF signals. For example, the dual-sidedpackage 100 can be implemented as a power amplifier (PA) module, alow-noise amplifier (LNA) module, a front-end module (FEM), a switchingmodule, etc. An overmold 105 may be formed and/or implemented in theunderside volume (where the semiconductor die 104 is located) formed bythe solder balls 106 (e.g., formed by a set of through-mold connections,such as a BGA). In one embodiment, the overmold 105 may encapsulate atleast a portion of the semiconductor die 104. For example, the overmold105 may fully or partially encapsulate the semiconductor die 104. Inanother embodiment, the overmold 105 may encapsulate at least a portionof the solder balls 106 (e.g., through-mold connections). For example,the overmold 105 may fully or partially encapsulate the solder balls106. As discussed above, the overmold 105 and/or the solder balls 106(e.g., the exposed portions of the solder balls 106) may form a landgrid array (LGA) type/style package. A close-up view of the solder balls106 and additional details (of the solder balls 106) areillustrated/discussed above in conjunction with FIG. 2.

FIG. 17 shows a dual-sided package 100 that can be a more specificexample of the dual-sided package of FIG. 16. In the example of FIG. 17,the semiconductor die 104 mounted under a packaging substrate 402 can bea die having one or more LNAs and one or more switches. In someembodiments, such a dual-side package can be implemented as a modulehaving LNA-related functionalities, including, for example, an LNAmodule. An overmold 105 may be formed and/or implemented in theunderside volume (where the semiconductor die 104 is located) formed bythe solder balls 106 (e.g., formed by a set of through-mold connections,such as a BGA). In one embodiment, the overmold 105 may encapsulate atleast a portion of the semiconductor die 104. For example, the overmold105 may fully or partially encapsulate the semiconductor die 104. Inanother embodiment, the overmold 105 may encapsulate at least a portionof the solder balls 106 (e.g., through-mold connections). For example,the overmold 105 may fully or partially encapsulate the solder balls106. As discussed above, the overmold 105 and/or the solder balls 106(e.g., the exposed portions of the solder balls 106) may form a landgrid array (LGA) type/style package. A close-up view of the solder balls106 and additional details (of the solder balls 106) areillustrated/discussed above in conjunction with FIG. 2.

FIG. 18A illustrates a top-down perspective view of an underside of adual-sided package 1805, according to some embodiments. In oneembodiment, the dual-sided package 1805 may result from thefabrication/manufacturing process illustrated in FIGS. 9A-9L and10A-10L. The dual sided package includes a substrate on which an upperportion (collectively indicated as 356) are formed, as discussed above.The solder balls 106 and the overmold 105 may be implemented on asurface of the upper portion 356, as discussed above. The solder balls106 may be arranged around a region 1806. A component (e.g., component104 discussed above) may be located under the overmold 105 in the region1806. The solder balls 106 may be arranged such that the solder balls106 form a rectangular perimeter around the region 1806. For example, afirst group of solder balls may form a rectangular perimeter around theregion 1806 (e.g., the inner rectangular perimeter of solder balls 106).A second group of solder balls 106 may form a rectangular perimeteraround the first group of solder balls 106 (e.g., the outer rectangularperimeter of solder balls 106).

As illustrated in FIG. 18A, the solder balls 106 are exposed through theovermold 105. For example, portions of the solder balls 106 may beremoved when portions of the overmold 105 are removed during afabrication/manufacturing process/state, as discussed above. The top ofthe remaining portions of the solder balls 106 may be visible after theportions of the overmold 105 are removed.

FIG. 18B illustrates a top-down perspective view of an underside of adual-sided package 1810, according to some embodiments. In oneembodiment, the dual-sided package 1810 may result from thefabrication/manufacturing process illustrated in FIGS. 11A-11M and12A-12F. The dual sided package includes a substrate on which an upperportion (collectively indicated as 356) are formed, as discussed above.The solder balls 106 and the overmold 105 may be implemented on asurface of the upper portion 356, as discussed above. The solder balls106 may be arranged around a region 1811. A component (e.g., component104 discussed above) may be located under the overmold 105 in the region1811. The solder balls 106 may be arranged such that the solder balls106 form a rectangular perimeter around the region 1811. For example, afirst group of solder balls may form a rectangular perimeter around theregion 1811 (e.g., the inner rectangular perimeter of solder balls 106).A second group of solder balls 106 may form a rectangular perimeteraround the first group of solder balls 106 (e.g., the outer rectangularperimeter of solder balls 106).

As illustrated in FIG. 18A, the solder balls 106 are exposed through theovermold 105. Also as illustrated, portions of the overmold 105 inregions around each solder ball 106 (e.g., in a circular region aroundeach solder ball 106) have been removed, as discussed above. Removingthe portions of the overmold 105 in the regions around each solder ball106 may create a gap (e.g., a torus/donut shaped gap between each solderball 106 and the overmold 105, as discussed above.

FIG. 18C illustrates a bottom-up close-up perspective view of a portionof an underside of a dual-sided package 1815, according to someembodiments. In one embodiment, the dual-sided package 1810 may resultfrom the fabrication/manufacturing process illustrated in FIGS. 13A-13C.The dual sided package includes a substrate on which an upper portion(collectively indicated as 356) are formed, as discussed above. Thesolder balls and the overmold 105 may be implemented on a surface of theupper portion 356, as discussed above. Additional conductive material118 may be formed, implemented, deposited, etc., on top of the solderballs, as discussed above in conjunction with FIGS. 13A-13C. Theadditional conductive material 118 may result in a dome shape thatprotrudes above the surface of the overmold 105. For example, the heightof the conductive material 118 may be greater than the height of theovermold 105.

Although the examples, embodiments, implementations, and/orconfigurations described herein may illustrate a component (e.g.,component 104 illustrated in FIG. 1) positioned in a middle of a surfaceof a module and may illustrate through-mold connections (e.g., contactfeatures, solder balls, pillars, etc.) positioned around the component,one having ordinary skill in the art understands that the positions,sizes, positioning/placements, and/or number of the through-moldconnections and/or components may vary. For example, a component may notbe located in the middle of a surface of a module and may be locatedalong an outer edge (e.g., a left edge) of the surface of the module. Inanother example, through-mold connections (e.g., solder balls, pillars,contact features, etc.) may be located in the middle of the surface of amodule (e.g., may be located where component 104 is located in FIG. 6B).

FIGS. 19 and 20 show examples of how the dual-sided package 100illustrated in the figures can be implemented in wireless devices. FIG.19 shows that in some embodiments, a dual-sided package having one ormore features as described herein can be implemented as a diversityreceive (RX) module 100. Such a module can be implemented relativelyclose to a diversity antenna 420 so as to minimize or reduce lossesand/or noise in a signal path 422.

The diversity RX module 100 can be configured such that switches 410 and412, as well as LNAs 414, are implemented in a semiconductor die(depicted as 104) that is mounted underneath a packaging substrate.Filters 400 can be mounted on such a packaging substrate as describedherein.

As further shown in FIG. 19, RX signals processed by the diversity RXmodule 100 can be routed to a transceiver through a signal path 424. Inwireless applications where the signal path 424 is relatively long andlossy, the foregoing implementation of the diversity RX module 100 closeto the antenna 420 can provide a number of desirable features.

FIG. 20 shows that in some embodiment a dual-sided package having one ormore features as described herein can be implemented in other types ofLNA applications. For example, in an example wireless device 500 of FIG.20, an LNA or LNA-related module 100 can be implemented as a dual-sidedpackage as described herein, and such a module can be utilized with amain antenna 524.

The example LNA module 100 of FIG. 20 can include, for example, one ormore LNAs 104, a bias/logic circuit 432, and a band-selection switch430. Some or all of such circuits can be implemented in a semiconductordie that is mounted under a packaging substrate of the LNA module 100.In such an LNA module, some or all of duplexers 400 can be mounted onthe packaging substrate so as to form a dual-sided package having one ormore features as described herein.

FIG. 20 further depicts various features associated with the examplewireless device 500. Although not specifically shown in FIG. 20, adiversity RX module 100 of FIG. 19 can be included in the wirelessdevice 500 with the LNA module 100, in place of the LNA module 100, orany combination thereof. It will also be understood that a dual-sidedpackage having one or more features as described herein can beimplemented in the wireless device 500 as a non-LNA module.

In the example wireless device 500, a power amplifier (PA) circuit 518having a plurality of PAs can provide an amplified RF signal to a switch430 (via duplexers 400), and the switch 430 can route the amplified RFsignal to an antenna 524. The PA circuit 518 can receive an unamplifiedRF signal from a transceiver 514 that can be configured and operated inknown manners.

The transceiver 514 can also be configured to process received signals.Such received signals can be routed to the LNA 104 from the antenna 524,through the duplexers 400. Various operations of the LNA 104 can befacilitated by the bias/logic circuit 432.

The transceiver 514 is shown to interact with a baseband sub-system 510that is configured to provide conversion between data and/or voicesignals suitable for a user and RF signals suitable for the transceiver514. The transceiver 514 is also shown to be connected to a powermanagement component 506 that is configured to manage power for theoperation of the wireless device 500. Such a power management componentcan also control operations of the baseband sub-system 510.

The baseband sub-system 510 is shown to be connected to a user interface502 to facilitate various input and output of voice and/or data providedto and received from the user. The baseband sub-system 510 can also beconnected to a memory 504 that is configured to store data and/orinstructions to facilitate the operation of the wireless device, and/orto provide storage of information for the user.

A number of other wireless device configurations can utilize one or morefeatures described herein. For example, a wireless device does not needto be a multi-band device. In another example, a wireless device caninclude additional antennas such as diversity antenna, and additionalconnectivity features such as Wi-Fi, Bluetooth, and GPS.

General Comments

Unless the context clearly requires otherwise, throughout thedescription and the claims, the words “comprise,” “comprising,” and thelike are to be construed in an inclusive sense, as opposed to anexclusive or exhaustive sense; that is to say, in the sense of“including, but not limited to.” The word “coupled”, as generally usedherein, refers to two or more elements that may be either directlyconnected, or connected by way of one or more intermediate elements.Additionally, the words “herein,” “above,” “below,” and words of similarimport, when used in this application, shall refer to this applicationas a whole and not to any particular portions of this application. Wherethe context permits, words in the above Description using the singularor plural number may also include the plural or singular numberrespectively. The word “or” in reference to a list of two or more items,that word covers all of the following interpretations of the word: anyof the items in the list, all of the items in the list, and anycombination of the items in the list.

The above detailed description of embodiments of the invention is notintended to be exhaustive or to limit the invention to the precise formdisclosed above. While specific embodiments of, and examples for, theinvention are described above for illustrative purposes, variousequivalent modifications are possible within the scope of the invention,as those skilled in the relevant art will recognize. For example, whileprocesses or blocks are presented in a given order, alternativeembodiments may perform routines having steps, or employ systems havingblocks, in a different order, and some processes or blocks may bedeleted, moved, added, subdivided, combined, and/or modified. Each ofthese processes or blocks may be implemented in a variety of differentways. Also, while processes or blocks are at times shown as beingperformed in series, these processes or blocks may instead be performedin parallel, or may be performed at different times.

The teachings of the invention provided herein can be applied to othersystems, not necessarily the system described above. The elements andacts of the various embodiments described above can be combined toprovide further embodiments.

While some embodiments of the inventions have been described, theseembodiments have been presented by way of example only, and are notintended to limit the scope of the disclosure. Indeed, the novel methodsand systems described herein may be embodied in a variety of otherforms; furthermore, various omissions, substitutions and changes in theform of the methods and systems described herein may be made withoutdeparting from the spirit of the disclosure. The accompanying claims andtheir equivalents are intended to cover such forms or modifications aswould fall within the scope and spirit of the disclosure.

What is claimed is:
 1. A packaged radio-frequency device comprising: apackaging substrate configured to receive one or more components, thepackaging substrate including a first side and a second side; a shieldedpackage implemented on the first side of the packaging substrate, theshielded package including a first circuit and a first overmoldstructure, the shielded package configured to provide radio-frequencyshielding for at least a portion of the first circuit; a set ofthrough-mold connections implemented on the second side of the packagingsubstrate, the set of through-mold connections defining a mountingvolume on the second side of the packaging substrate; a componentimplemented within the mounting volume; and a second overmold structuresubstantially encapsulating the set of through-mold connections so thatat least a portion of the set of through-mold connections is exposedthrough the second overmold structure, the set of through-moldconnections including a ball grid array, the ball grid array including afirst group of solder balls arranged to partially or fully surround thecomponent, at least some of the first group of solder balls electricallyconnected to input and output nodes of the first circuit.
 2. Theradio-frequency device of claim 1 wherein the set of through-moldconnections includes a metallic material.
 3. The radio-frequency deviceof claim 1 wherein the set of through-mold connections includes a set ofpillars configured to allow the packaged radio-frequency device to bemounted on a circuit board.
 4. The radio-frequency device of claim 1wherein the first and second sides of the packaging substrate correspondto upper and lower sides, respectively, when the packagedradio-frequency device is oriented to be mounted on a circuit board. 5.The radio-frequency device of claim 1 wherein the ball grid array isconfigured to allow the packaged radio-frequency device to be mounted ona circuit board.
 6. The radio-frequency device of claim 5 wherein theball grid array further includes a second group of solder balls arrangedto partially or fully surround the first group of solder balls.
 7. Theradio-frequency device of claim 6 wherein each of the second group ofsolder balls is electrically connected to a ground plane within thepackaging substrate.
 8. The radio-frequency device of claim 7 whereinthe first group of solder balls forms a rectangular perimeter around thecomponent mounted on the second side of the packaging substrate.
 9. Theradio-frequency device of claim 8 wherein the second group of solderballs forms a rectangular perimeter around the first group of solderballs.
 10. The radio-frequency device of claim 1 wherein the firstovermold structure substantially encapsulates the first circuit.
 11. Theradio-frequency device of claim 10 wherein the shielded package furtherincludes an upper conductive layer implemented on the first overmoldstructure, the upper conductive layer electrically connected to a groundplane within the packaging substrate.
 12. The radio-frequency device ofclaim 11 wherein the upper conductive layer and the ground plane areelectrically connected through a conformal conductive coatingimplemented on one or more sides of the first overmold structure
 13. Theradio-frequency device of claim 12 wherein the conformal conductivecoating extends to corresponding one or more sides of the packagingsubstrate.
 14. The radio-frequency device of claim 11 wherein the upperconductive layer and the ground plane are electrically connected throughone or more conductors within the first overmold structure.
 15. Theradio-frequency device of claim 14 wherein the one or more conductorsinclude shielding wirebonds arranged relative to the first circuit toprovide radio-frequency shielding functionality for at least a portionof the first circuit.
 16. The radio-frequency device of claim 14 whereinthe one or more conductors include one or more surface-mount technologydevices mounted on the packaging substrate, the one or moresurface-mount technology devices arranged relative to the first circuitto provide radio-frequency shielding functionality for at least aportion of the first circuit.
 17. A wireless device comprising: acircuit board configured to receive a plurality of packaged modules; anda radio-frequency module mounted on the circuit board, theradio-frequency module including a packaging substrate configured toreceive a plurality of components, the packaging substrate including afirst side and a second side, the radio-frequency module furtherincluding a shielded package implemented on the first side of thepackaging substrate, the shielded package including a first circuit anda first overmold structure, the shielded package configured to provideradio-frequency shielding for at least a portion of the first circuit,the radio-frequency module further including a set of through-moldconnections implemented on the second side of the packaging substrate,the set of through-mold connections defining a mounting volume on thesecond side of the packaging substrate, the radio-frequency modulefurther including a component implemented within the mounting volume anda second overmold structure substantially encapsulating the set ofthrough-mold connections so that at least a portion of the set ofthrough-mold connections is exposed through the second overmoldstructure, the set of through-mold connections including a ball gridarray, the ball grid array including a first group of solder ballsarranged to partially or fully surround the component, at least some ofthe first group of solder balls electrically connected to input andoutput nodes of the first circuit.